1. Field of the Invention
The invention relates to electromagnetic positioners and refers more specifically to an electromagnetic positioner for a drive arm of an electrohydraulic servo valve or the like constructed and arranged so that the work output for a given input signal is maximized within an envelope having a width and depth not larger than the valve body and a minimum height.
2. Description of the Prior Art
Electromagnetic positioners are often designed with the output work required for an input signal, that is, the movement of a drive arm in relation to a variable input signal, and a structure envelope being given.
The input to such devices is normally an analog signal which manifests itself as ampere turns as applied to control coils of the positioner. The work is then one-half of the ampere turns times the magnetic flux passing through the coils of the positioner if a linear relationship is assumed between flux and ampere turns.
The output of such devices is a displacement of a drive arm tip proportional to the number of applied ampere turns. The output work is one-half of the distance the drive arm tip is displaced times the force required to move the drive arm tip back to a null position, again assuming a linear relationship.
With a maximum output signal for a given input signal being attained and the width and depth of a valve body on which the electromagnetic positioner is used being determined, a minimum envelope may then be accomplished by minimizing the height of the envelope, that is, the height of the electromagnetic positioner structure, since the electromagnetic positioner structure is usually limited in width and depth dimensions by valve body dimensions.
The electromagnetic positioner of the invention has been particularly constructed and designed to provide a minimum envelope vertical height consistent with maximum output from a given input signal.